How Crowfoot Wrench Sizes Work The size (1‑1/8") refers to the opening of the jaw — the nut or bolt head it fits. So this wrench is meant for a 1‑1/8" fastener. Drive size (3/8") refers to the square hole where you attach a ratchet or torque wrench. In this case, it takes a 3/8" drive tool. Length is simply the overall measurement of the wrench body from end to end. It doesn’t affect fitment, but longer ones give more reach. Example Breakdown for Your Wrench Jaw Opening: 1‑1/8" → fits a nut/bolt head that size. Drive Size: 3/8" → attaches to a 3/8" ratchet/extension. Length: whatever the manufacturer lists (often 2–3"), just the physical size of the tool. ✅ So in plain terms: This crowfoot wrench is a 1‑1/8" wrench head that snaps onto a 3/8" ratchet, with a body length of about 2–3".